Water treatment system

Abstract

The embodiments of this disclosure are related to a water treatment system comprising a flotation tank, a shell-tube inlet conduit connected to the flotation tank and comprising a shell configured to supply a gas and at least one tube configured to supply untreated water, wherein each of the shell and the tube has a first part exposed to an outside of the flotation tank and a second part extending into the flotation tank, a microbubble forming means positioned on or adjacent to the second part of the shell, and a treated water outlet connected to the flotation tank and configured to allow treated water separated from solids in the flotation tank to be discharged therethrough.

What is claimed is: 
     
         1 . A water treatment system, comprising:
 a flotation tank;   a shell-tube inlet conduit connected to the flotation tank and comprising a shell configured to supply a gas and at least one tube configured to supply untreated water, wherein each of the shell and the tube has a first part exposed to an outside of the flotation tank and a second part extending into the flotation tank;   a microbubble forming means positioned on or adjacent to the second part of the shell; and   a treated water outlet connected to the flotation tank and configured to allow treated water separated from solids in the flotation tank to be discharged therethrough.   
     
     
         2 . The water treatment system of  claim 1 , wherein the flotation tank has a predetermined height,
 the shell-tube inlet conduit is connected to a lower part of the flotation tank, and   the second part of each of the shell and the tube extend from a bottom of the flotation tank to a position corresponding to at least 25% from the bottom of the height of the flotation tank.   
     
     
         3 . The water treatment system of  claim 1 , wherein the at least one tube is a single tube. 
     
     
         4 . The water treatment system of  claim 1 , wherein the shell-tube inlet conduit further comprises a support installed between the shell and the at least one tube and configured to hold the at least one tube and maintain a separation distance therebetween. 
     
     
         5 . The water treatment system of  claim 1 , wherein a ratio of a diameter of the second part of the tube to a diameter of the second part of the shell is in a range of 1:1.1 to 1:3. 
     
     
         6 . The water treatment system of  claim 1 , wherein the position of the second end of the tube is higher than that of the second end of the shell. 
     
     
         7 . The water treatment system of  claim 1 , wherein the microbubble forming means is positioned on the second part of the shell or adjacent to the second part of the shell. 
     
     
         8 . The water treatment system of  claim 1 , wherein the microbubble forming means comprises a membrane diffuser, an electroflotation device, a shear flotation (SF) device, a pressurized flotation device, or a combination thereof. 
     
     
         9 . The water treatment system of  claim 1 , wherein the treated water outlet is formed at a position lower than the second end of the shell, the second end of the tube, or the microbubble forming means. 
     
     
         10 . The water treatment system of  claim 1 , further comprising:
 a floating solid recovery means.   
     
     
         11 . A method to treat water using the water treatment system according to  claim 1 . 
     
     
         12 . The method of  claim 11 , comprising:
 introducing untreated water into the flotation tank through the tube;   supplying gas through the shell from the outside into the flotation tank;   forming microbubbles by passing the gas through the microbubble forming means; and   discharging the treated water to the outside of the flotation tank.   
     
     
         13 . The method of  claim 11 , wherein a ratio of an inflow rate of the untreated water to an inflow rate of the gas is in a range of 1:1 to 6:1. 
     
     
         14 . The method of  claim 11 , wherein a size of microbubbles formed from the microbubble forming means is equal to or less than 100 μm. 
     
     
         15 . The method of  claim 11 , wherein an outflow rate of the treated water discharged through the treated water outlet is equal to or less than an inflow rate of the untreated water introduced through the tube.